1. Field of the Disclosure
Aspects of the present invention generally relate to a subject detection device and a control method for the same, an imaging apparatus to which the subject detection device is applied, and the like.
2. Description of the Related Art
It has been known that in a subject detection device such as a video camera, a region having a particular pattern such as a human face (subject region) is detected based on an image signal generated in an imaging element. It has also been known that based on the detected subject region, controls including the automatic focusing (AF) control and the automatic exposure (AE) control are conducted and a frame defining the subject region is displayed. Furthermore, in order to increase the degree of freedom of the subject, a subject other than the human face can also be detected. For example, Japanese Patent Application Laid-Open No. 2009-211311 has disclosed image processing apparatus and method that detect the upper half of a human body.
For improving the detection accuracy, Japanese Patent Application Laid-Open No. 2008-40710 has disclosed a method of detecting a subject having a particular pattern while compensating various drawbacks by a first detection method using hardware (luminance information) and a second detection method using software (color information) with respect to the subject.
When the subject is detected, the detection state and the non-detection state may be repeated depending on the state of the subject. In this case, since the display and the non-display of the detection frame representing the subject detection result are switched repeatedly, the frame display flickers on the display screen. Further, when AF control or AE control is performed on the detected subject, the presence or absence of the control target changes repeatedly; therefore, the control may be unstable. In particular, as for the subject that is as small as the lower limit of the size capable of subject detection, the detection state may be unstable in the occurrence of the minute change of the subject size.